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Sweet viburnum will quickly form a solid hedge.  It is by far the most frequently used plant to form a tight wall.
Sweet viburnum is a fast growing shrub and requires regular pruning to maintain the full, clean appearance.
Sweet Viburnum, Viburnum odoratissimum

Alex Driscoll
Certified Arborist #1249A
Plant Guide /Landscape Shrubs / Sweet Viburnum